Metal disc and baseplate bindings require a different approach than their plastic/fiberglass counterparts. You tighten metal on plastic, you are done.
With these metal bindings, you have zero play in the parts, everything is metal on metal with the screws and the inserts. Then you are subjecting these metal parts to extreme temperature changes.
There are ways to solve this problem, finger it out.
Also metal underfoot is just far less comfy than plastic, I don't care what anybody says.
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